1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device.
2. Description of the Related Art
Miniaturization of semiconductor devices greatly depends on the photolithography employed to manufacture the devices. Therefore, it is generally difficult to form line-and-space patterns that have widths smaller than the minimum width attained by the resolution limit of photolithography.
To solve this problem, a method has been proposed. In this method, a sidewall pattern is formed on the sidewall of a dummy pattern and is used as mask to perform etching. (See, for example, U.S. Pat. No. 6,063,688.) This method can indeed provide a line-and-space pattern in which the lines are formed at half the line pitch of the dummy pattern.
However, this method is not designed for patterns other than line-and-space patterns. Inevitably, it cannot form a pattern including line-and-space pattern and patterns of other types, reliably or efficiently.
Thus, it has been difficult to form patterns reliably and efficiently, rendering it difficult to manufacture excellent semiconductor devices.